So it shouldn't really come as a surprise that the man whom every script wants to read, Russell Crowe, is to play both the Sheriff of Nottingham and his philanthropic nemesis in the new Ridley Scott reworking of the Robin Hood fable, putting the hotly-tipped Christian Bale out of the running.

"I think it will have the same propulsion that Gladiator had - the same adrenaline hits."

I'm all for actors playing dual roles. It has worked in several films where it has thematic relevance. But Crowe's ego precedes him, and it's tempting to believe he just wants to share screen time with himself.

Thinking of actors in a dual role immediately brings to mind the harrowing headfuck that was David Cronenberg's Dead Ringers, with Jeremy Irons giving a nuanced and troubling performance as twin gynaecologists Beverley and Elliot Mantle, armed with HR Giger-esque surgical hardware. So engrossing is the personality split embodied (pun intended) by Irons that the fact that the roles are being played by the same actor becomes an irrelevance.

Lighthearted use of the dual role has a long pedigree (from Alec Guinness to Peter Sellers to Mike Myers, and done to death by Eddie Murphy) and since this is what the device is best known for, it will be difficult for an actor who apparently takes himself as seriously as Crowe does to lift the performance above absurdity.

Charlie Kaufman's satirical drama Adaptation is an interesting addition to the canon, since it's self-referential use of the device collapses in on itself, due to the nature of Kaufman's script, and Spike Jonze's at times overambitious direction. That's not to say Ridley Scott isn't capable of directing Crowe in two roles of what, if Grazer is to be believed, will be a far more linear story.

The Nottingham dual-role decision isn't borne of a plot device robust enough to warrant the same actor in both roles. According to Scott, his revisionist version will be "a good old clever adjustment of characters. One becomes the other. It changes".

While this will be a Hollywood (re)telling of a good, old-fashioned tale, it doesn't lend itself to the device in the fantastical, knowing pantomime sense (Mr Darling and Captain Hook played by the same actor in stage adaptations of Peter Pan, for instance). Nor will allowing this high profile actor to literally face himself add any deeper meaning to the battle between sheriff and outlaw, no matter who is cast as the hero. The device itself risks eclipsing the characters' adversarial development.

And anyway, wasn't this new adaptation's whole shtick the fact that noble Robin Hood is the baddie? Let's have an "evil" Robin Hood we can revel in, then, like Alan Rickman's delicious (and film-stealing) take on the Sheriff in Kevin Costner's version. I can't help thinking Bale might enjoy adding a little maniacal glee to his dark side.

Crowe will no doubt put in a rousing performance as the heroic Sheriff, as he did in Gladiator. But let another actor be his nemesis. He's a solid performer - he can give us that propulsion, that adrenalin hit - but rarely in film (unlike the stage) should it be necessary or welcome for an actor to provide a foil for himself.